cool#9992 lok doc sign: async DocumentDigitalSignatures::ImplViewSignatures()

Currently SfxObjectShell::CheckIsReadonly() has a hack for the LOK case
to show the signatures dialog read-only, as only that is async.

The next step is to make DocumentDigitalSignatures::ImplViewSignatures()
async, though that requires all callers of the function to be async, so
make DocumentDigitalSignatures::signScriptingContent() async as well.
There is also DocumentDigitalSignatures::signPackage(), but turns out
that's dead code, so just remove it.

Once this is in place, we had a problem that the callbacks tried to
interact with libxmlsec, but the dialog was still alive in
DocumentDigitalSignatures::ImplViewSignatures() by the time the callback
was running, so there were two DocumentSignatureManager instances at the
same time, and both assumes it should call the global libxmlsec
init/uninit, which resulted in failing to verify the just created
signature.

Fix this similar to how Tomaz fixed the same problem around pdfium in
commit 067a8a954c8e1d8d6465a4ab5fb61e93f16c26c2 (pdfium: only init
pdfium library one and destroy on LO exit, 2020-06-03).

Change-Id: I3fb63c06195564732e1576dbd755157e676fb762
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/173117
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>

1 files changed, 29 insertions, 2 deletions

diff --git a/xmlsecurity/source/helper/documentsignaturemanager.cxx b/xmlsecurity/source/helper/documentsignaturemanager.cxx
index 620c85458afe..f3931a9cdd31 100644
--- a/xmlsecurity/source/helper/documentsignaturemanager.cxx
+++ b/xmlsecurity/source/helper/documentsignaturemanager.cxx
@@ -56,6 +56,33 @@ using namespace css;
 using namespace css::graphic;
 using namespace css::uno;
 
+/// RAII class to init / shut down libxmlsec.
+class Xmlsec
+{
+public:
+    Xmlsec();
+    ~Xmlsec();
+};
+
+Xmlsec::Xmlsec() { initXmlSec(); }
+
+Xmlsec::~Xmlsec() { deInitXmlSec(); }
+
+namespace
+{
+/// Shared access to libxmlsec, to avoid double init.
+struct XmlsecLibrary
+{
+    static std::shared_ptr<Xmlsec>& get();
+};
+
+std::shared_ptr<Xmlsec>& XmlsecLibrary::get()
+{
+    static std::shared_ptr<Xmlsec> pInstance = std::make_shared<Xmlsec>();
+    return pInstance;
+}
+}
+
 DocumentSignatureManager::DocumentSignatureManager(
     const uno::Reference<uno::XComponentContext>& xContext, DocumentSignatureMode eMode)
     : mxContext(xContext)
@@ -64,7 +91,7 @@ DocumentSignatureManager::DocumentSignatureManager(
 {
 }
 
-DocumentSignatureManager::~DocumentSignatureManager() { deInitXmlSec(); }
+DocumentSignatureManager::~DocumentSignatureManager() { mpXmlsecLibrary.reset(); }
 
 bool DocumentSignatureManager::init()
 {
@@ -76,7 +103,7 @@ bool DocumentSignatureManager::init()
                 "DocumentSignatureManager::Init - mxGpgSEInitializer already set!");
 
     // xmlsec is needed by both services, so init before those
-    initXmlSec();
+    mpXmlsecLibrary = XmlsecLibrary::get();
 
     mxSEInitializer = xml::crypto::SEInitializer::create(mxContext);
 #if HAVE_FEATURE_GPGME